Switch AI price check to Haiku for cost and speed

Testing Haiku 4.5 for catalog price analysis — structured JSON output
with explicit rules is well within its capabilities. Revert to Sonnet
if result quality is insufficient.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Infrastructure/Services/AiCatalogPriceCheckService.cs

@@ -20,7 +20,7 @@ public class AiCatalogPriceCheckService : IAiCatalogPriceCheckService
     private readonly IConfiguration _config;
     private readonly ILogger<AiCatalogPriceCheckService> _logger;
 
-    private const string Model = "claude-sonnet-4-6";
+    private const string Model = "claude-haiku-4-5-20251001";
     private const int BatchSize = 25;
     private const int MaxConcurrentBatches = 1; // Tier 1 output limit is 8,000 TPM — sequential avoids bursting past it
     private const int RateLimitRetrySeconds = 65; // wait just past the 60s window before retrying a 429